1. A proton is located at a distance of 0.420 m
from a point charge of +8.30 microcoulumbs. The repulsive electric
force moves the proton until it is at a distance of 1.58 m from the
charge. Suppose that the electric potential energy lost by the system
is caried off by a photon that is emitted during the process. What is
its wavelenth?
Ans. 9.53 x 10-12 m
2. The maximum wavelength that an electromagnetic wave can have and
still eject electrons from a metal surface is 485 nm. What is the
work function of this metal? Express your answer in electron
volts.
Ans. 2.56 eV
3. The de Broglie wavelength of a proton in a particle accelerator is
1.30 x 10-14m. Determine the kinetic energy (in joules) of
the proton.
Ans. 7.79 x 10-13 J
4.When light with a frequency f1 = 547.5 THz illuminates a
metal surface the most energetic photoelectrons have 1.260 x
10-19 J of kinetic energy. When light with a frequency
f2 = 738.8 THz is used instead, the most energetic
photoelectrons have 2.480 x 10-19J of kinetic energy.
Using these experimental results, determine the approximate value of
Planck's constant.
Ans. 6.377 x 10-34 Js
5. An X-ray photon with a wavelength of 0.650 nm scatters from a free
electron at rest. After scattering, the photon moves at an angle of
152o relative to the incident direction. Find a) the
wavelength and b) the energy of the scattered photon. c) Determine
the kinetic energy of the recoiling electron.
Ans. .655 nm, 3.04 x 10-16J, 2 x 10-18J
6. If the speed of an object is 35.0 m/s, with an uncertainty of
5.00%, what is the minimum uncertainty in the object's position if it
is a) an electron, or b) a volleyball (m = .350 kg)?
Ans. 6.64 x 10-5 m, 1.72 x 10-34m
7. Plutonium 23994Pu (atomic mass = 239.05216
u) undergoes alpha
decay. Assuming that all the released energy is in the form of
kinetic energy of the alpha particle (atomic mass = 4.002603 u) and ignoring the recoil of the
daughter nucleus, find the speed of the a particle. Ignore relativistic effects. (atomic mass of 23592U is 235.043924 u)
Ans. 1.59 x 107 m/s